Production of technical white mineral oil

ABSTRACT

Technical grade white mineral oil is produced by a series of steps including treating a mineral lubricating oil distillate with hydrogen in the presence of a sulfur-resistant catalyst (e.g., nickel molybdate on alumina) under hydrorefining conditions. The hydrogenated oil is hydroisomerized and hydrocracked by contact with hydrogen in the presence of a silica-alumina and crystalline-aluminosilicate-containing catalyst having about 0.1 to 5 weight percent of a platinum group metal. The resulting product is further contacted with hydrogen under aromatic saturation conditions in the presence of a platinum group metal-containing hydrogenation catalyst (e.g., platinum on alumina).

United ,States Patent 1 3,629,096

72 Inventor JosephM.Divljak,Jr. 3,301,917 1/1967 Wise 260/683.65

Grifiith, Ind. 3,308,052 3/1967 lreland et al. 208/27 [21] Appl. No.647,628 3,459,656 8/1969 Rausch 208/57 [22] Filed June 21, 19672,779,713 1/1957 Cole et al... 208/57 [45] Patented Dec. 21, 19712,967,147 1/1961 Cole 208/144 [73] Assignee Atlantic Richiield Company3,340,181 9/1967 Diringer et al 208/210 Primary Examiner-Delbert E.Gantz [541 PRODUCTION or TECHNICAL WHITE MINERAL 4mm"! Examiner-QCrasanakis 01L Attorney-Morton, Bernard, Brown, Roberts & Sutherland 8Claims, No Drawings Technical grade white mineral is produced 208/210 bya series of steps including treating a mineral lubricating oil [51]lnt.Cl ..C10g3l/ 14, di ill t ith hydrogen in the presence of asulfur-resistant g l5/02 catalyst (e.g., nickel molybdate on alumina)under hydrorefin- 0 Search l8, conditions The hydrogenatgd is hydoisomerized and 57. 46 260/633-65 hydrocracked by contact with hydrogenin the presence of a silica-alumina andcrystalline-aluminosilicate-containin [56] References cued catalysthaving about 0.1 to 5 weight percent of a platinun? UNITED STATESPATENTS group metal. The resulting product is further contacted with3,487,005 12/1969 Egan et al. 208/59 hydrogen under aromatic saturationconditions in the 3,125,51 1 3/1964 Tupman et al. 208/264 presence of aplatinum group metal-containing hydrogenation 3,268,439 8/1966 Tupman eta1 208/1 [2 catalyst (e.g., platinum on alumina).

PRODUCTION OF TECHNICAL WHITE MINERAL OIL This invention relates to aprocess for the'production of technical grade white mineral oil fromraw, waxy mineral oil distillates. More particularly, this inventionconcerns a hydrorefining, hydroisomerization-hydrocracking, aromaticsaturation, catalytic conversion process for the production of technicalgrade white mineral oil in increased yields and at reduced operatingcosts.

Conventional refining techniques employed in producing technical gradewhite lubricating oils from raw, waxy distillates involve, for example,solvent treating, solvent dewaxing, and severe acid treating. Theseconventional refining techniques suffer from many shortcomings. Forexample, acid treating and solvent extraction have the inherentdisadvantage of producing relatively low value byproduct sludge orextracts, and solvent dewaxing is a relatively costly operation due tohigh refrigeration requirements and low filter rates. Other techniques,such as urea adduction, encounter great difficulties as a continuousprocess for refining raw, waxy lubricating oil distillates.

The present invention concerns a hydrorefining,hydroisomerization-hydrocracking, aromatic saturation process wherein araw, waxy, lubricating oil distillate having a high pour point, and ahigh aromatic content is converted into a technical grade white mineraloil in increased yields and at reduced operating coats. According to theprocess of the present invention the raw, waxy, lubricating oildistillate is contacted in a first stage 'with hydrogen in the presenceof a desulfurization-denitrogenation type catalyst under hydrorefiningconditions and treated in a second stage with hydrogen in the presenceof a hydroisomerizationhydrocracking catalyst. The oil of lubricatingviscosity in the second stage product is further contacted in a thirdstage with hydrogen under aromatic saturation conditions to produce highquality technical grade white mineral oil.

The mineral lubricating oil distillates to be treated by the process ofthe present invention are raw, waxy lubricating oil distillates whichmay even represent the complete distillate lubricating oil fractionderived from a waxy crude oil. The lubricating oil distillates useful asfeedstocks in the present invention often possess a viscosity in therange of about 35 to 90 SUS at 2 F., an aromatic carbon content of aboutto 30 percent, a pour point of atleast about 70 F., and boil primarilyin the range of about 600 to 1,200 F.

The hydrorefining treatment in the first stage of the present process isconducted at temperatures of about 600 to 800 F., preferably about 675to 725 F, The other reaction conditions generally can include pressuresof about 500 to 3,000 p.s.i.g., preferably about 2,000 to 3,000p.s.i.g., weight hourly space velocities (WHSV) of about 0.2 to 2,preferably about 0.25 to 0.5; and molecular hydrogen to feed oil ratiosof about 1,000 to 5,000 SCF/B, preferably about 1,500 to 2,500 SCF/B.

According to my method the hydrogenated oil from the first hydrogenationstage is subjected to a second hydrogenation operation in which thecatalyst is such that hydroisomerization and hydrocracking are effected.Thus, temperatures in the second stage range from about 600 to 950 F.,with temperatures of about 650 to 800 F. being preferred. Other reactionconditions can include pressures of about 500 to 3,000 p.s.i.g.,preferably about 2,000 to 3,000 p.s.i.g., weight hourly space velocitiesof about 0.25 to 2, preferably about 0.25 to 0.5, and molecular hydrogento feed oilratio of about 1,000 to 5,000 SCF/B, preferably about 2,000to 3,000 SCF/B.

The aromatic saturation of the product of lubricating viscosity made inthe second stage is in the third stage of the operation of thisinvention, and is conducted at a temperature of about 450 to 700 F.,preferably about 550 to 600 F. Other reaction conditions can include apressure of about 500 to 3,000 p.s.i.g., preferably about 2,000 to 3,000p.s.i.g., a weight hourly space velocity of about 0.2 to 2, preferablyabout 0.25 to 0.5, and a hydrogen to feed oil rate of about 1,000 to5,000 SCF/B, preferably about 2,000 to 3,000 SCF/B.

The desulfurization-denitrogenation type catalysts used in the firststage of the present process can be the sulfur-resistant, nonpreciousmetal hydrogenation catalysts, such as those conventionally employed inthe hydrogenation of heavy petroleum oils. Examples of suitablecatalytic ingredients are tin, vanadium, members of Group VlB in thePeriodic Table, i.e. chromium, molybdenum and tungsten, and metals ofthe iron group, i.e. iron, cobalt and nickel. These metals are presentin catalytically effective amounts, for instance, about 2 to 30 weightpercent, and may be in elemental form or in combined form such as theoxides or sulfides, the sulfides being preferred. Mixtures of thesematerials or compounds of two or more of the oxides or sulfides can beemployed, for example, mixtures or compounds of the iron group metaloxides or sulfides with the oxides or sulfides of Group VlB constitutevery satisfactory catalysts. Examples of such mixtures or compounds arenickel molybdate, tungstate or chromate (or thiomolybdate,thio-tungstate or thiochromate) or mixtures of nickel or cobalt oxideswith molybdenum, tungsten or chromium oxides, As the art is aware and asthe specific examples below illustrate, these catalytic ingredients aregenerally employed while disposed upon a suitable carrier of the solidoxide refractory type, e.g., a predominantly calcined or activatedalumina or other base exerting little cracking effect. Commonly employedcatalysts have about 1 to 10 percent of an iron group metal and 5 to 25percent of a Group VlB metal (calculated as the oxide). Advantageously,the catalyst is nickel molybdate supported on alumina. Such preferredcatalyst can be prepared, for instance, by the method described in U.S.Pat. No. 2,938,002.

The platinum group metal-containing hydroisomerizationhydrocrackingcatalyst used in the second stage of the method of the presentinvention, unlike the catalyst employed in the first stage, is notnormally sulfur-resistant and contains a major amount of an amorphoussilica-alumina composite, containing for instance, about 5 to 45,preferably about 10 to 20, weight percent alumina on a dry basis; about3 to 25, preferably about 5 to 10, weight percent of a hydrogenexchangedcrystalline alumino-silicate having a silica-to-alumina mole ratiogreater than 3:1; and a catalytic amount, say about 0.1 to 5, preferablyabout 0.3 to 2, weight percent of a platinum group metal. The catalystmay also contain a small amount, e.g., less than about 1 weight percentof halide such as chloride or fluoride. If desired, a small amount, forinstance about 5 to 20 or more weight percent of a suitable bindermaterial, for example, alumina hydrogel, may be added to the secondstage catalyst composition especially if the catalyst is formed byextrusion.

The platinum group metals include such group VlIl metals as, forexample, platinum, palladium, rhodium, or iridium. The platinum groupmetal may be present in the metallic form or as a sulfide, oxide orother combined form, The metal may interact with other constituents ofthe catalyst, but if during use the platinum group metal is present inthe metallic form, then it is preferred that it be so finely dividedthat it is not detectable by X-ray defraction means, i.e. that it existsas crystallites of less than about 50 A. in size.

The amorphous silica-alumina composite employed in the second stagecatalyst of the process of the invention is usually syntheticallyprecipitated. The silica-alumina can be prepared by any desired methodand several procedures are known in the art. For instance, a hydrogelcan be prepared by coprecipitation or sequential precipitation by eithercomponent being the initial material precipitated with at least theprincipal part of the silica or alumina being made in the presence ofthe other, Generally the alumina is precipitated in the presence of asilica gel. It is preferred that the silica-alumina hydrogel be made byforming a silica hydrogel by precipitation from an alkali metal silicatesolution and an acid such as sulfuric acid. Then alum solution may beadded to the silica hydrogel slurry. The alumina is precipitated byraising the pH into the alkaline range by the addition of an aqueoussodium aluminate solution or by the addition of a base such as ammoniumhydroxide. Other techniques for preparing the silica-alumina are wellknown in the are, and these techniques may be used. In the finalcatalyst the silica-alumina is present in xerogel or catalyticallyactive form due to treatment at elevated temperatures as by calcinationof the hydrogel.

The crystalline aluminosilicate component of the second stage catalystmay be synthetic or naturally occurring and has a pore size of about 8to 15 A., preferably about 10 t 14 A. Usually, with a given material,the pores are relatively uniform in size and often the crystallinealumino-silicate particles used to make the catalyst are primarily lessthan about 15 microns in size, preferably less than about microns. 1nthe crystalline aluminosilicate, the silica-to-alumina mole ratio isgreater that 3:1 and is usually not above about 12:1, preferably beingabout 4 to 6:1. The aluminosilicate is at least about 50 percent,preferably at least about 75 percent, hydrogenexehanged. That is about50 percent of the metal cations, e.g. sodium, present in thealuminosilicate are replaced by hydrogen. Hydrogen exchange is commonlycarried out by exchange of the cations of the synthetic or naturallyoccurring aluminosilicates with ammonium ions, for instance throughcontact with an aqueous solution of ammonium chloride or otherwater-soluble ammonium compound and subsequently calcining thealuminosilicate.

One method of preparing the second stage catalyst is by combining thesilica-alumina hydrogel and the hydrogenexchanged crystallinealuminosilicate and drying the mixture, for instance at temperatures ofabout 230 to 600 F., to con vert the silica-alumina hydrogel to thexerogel form. The crystalline aluminosilicate may, if desired, behydrogenexchanged after it is combined with the silica-alumina hydrogel.The dried material can be calcined, for instance, at a temperature ofthe order of about 700 to 1500 F., preferably about 800 to 1,100" F. Theplatinum group metal may be added before or after the calcination, by,for example, ion exchange or impregnation, 1n any event, after theplatinum group metal is added, the catalyst can be dehydrated andactivated at the calcination temperature described above.

An available method for adding the platinum group metal by ion exchangecomprises treating the silica-aluminacrystalline alumino-silicatemixture with an aqueous solution containing complex water-soluble,metal-amine cations, both organic and inorganic, of the metal to bedeposited in the crystal structure. These complex cations ion-exchangewith the cations present in the crystalline aluminosilicate. Theexchange material is then removed from the solution, dried and activatedor calcined, for example, by heating the material up to a temperature ofabout 250 C. in a flowing stream ofinert dry gas or vacuum. Theactivation may be effected at a temperature below the temperature atwhich the complex cations are destroyed. The activated material may thenbe subjected to heat treatment to a temperature not exceeding about 650C. and preferably not exceeding about 500 C. in vacuum or inertatmosphere whereby the complex cation is destroyed and the platinumgroup metal is reduced in the material. Should the thermal treatment beinsufficient to reduce the metal of the complex cations to the elementalstate, chemical reduction either alone or in combination with thermalreduction may be employed. Alkali metals such sodium are suitablereducing agents for this purpose. Throughout the operation excessivetemperatures and extremes of acidity are to be avoided since they maytend to destroy the crystal structure ofthe silica-alumina-crystallinealuminosilicate mixture.

The platinum group metal may also be added by impregnation. Thesilica-alumina-crystalline aluminosilicate mixture, for example, eitherwith or without previous evacuation, may be soaked in either a dilute orconcentrated solution, usually aqueous chloroplatinic acid, ammoniumhexathiocyanoplatinate (1V) or hexathiocyanate platinic acid, often inan amountjust sufficient to wet the material and be completely absorbed.Also, ifdesired, the solution may be incorporated into thesilica-a1umina-crystalline aluminosilicate during the formation ofthelatter.

Either before of after dehydration, the catalyst can, if desired, beformed into macrosized particles by -inch or extruding. Generally, theseparticles are about l/32 inch to k inch in diameter and about l/16-inchto l-inch or more in length. Although these macrosized particles areusually formed after dehydration and before calcination, this, of courseis optional and can be done at any time found most convenient.

The catalyst employed in the third, or aromatic-saturation stage of thepresent invention is a platinum group metal-containing hydrogenationcatalyst. This catalyst, like the catalysts of the second stage, isdistinguished from the catalysts of the first stage in that it is notnormally considered to be sulfur-resistant. The catalyst includescatalytically effective amounts of the platinum group metals mentionedabove. Often, the platinum group metal is present in an amount, forexample, of about 0,01 to 2 weight percent, preferably about 0.1 to 1weight percent. The platinum group metal may be present in the metallicform or as a sulfide, oxide, or other combined form. As in the case ofthe second stage catalyst, the metal may interact with otherconstituents of the catalyst but if during use the platinum group metalis present in metallic form, then it is preferred that it be so finelydivided that it is not detectable by X-ray diffraction means, i.e. thatit exists as crystallites ofless than about 50 A. size. Of the platinumgroup metals, platinum is preferred. If desired, the catalysts employedin the third stage of the process of the invention, like the catalystsused in the first stage, can be prereduced prior to use by heating inthe presence of hydrogen, generally at temperatures of about 600 to 800F.

Although various solid refractory type carriers known in the art may beutilized as a support for the third stage platinum group metal, thepreferred supports have no substantial cracking effect on thehydrocarbon feeds. Most advantageously, the support is composedpredominantly of alumina of the activated or calcined type. The aluminabase is usually the major component of the catalyst, generallyconstituting at least about 75 weight percent on the basis of thecatalyst and preferably at least about to 99.8 percent. The aluminacatalyst base can be an activated or gamma family alumina, especiallygamma or eta alumina, such as those derived by calcination of amorphoushydrous alumina, alumina monohydrate, alumina trihydrate or theirmixtures. A catalyst base advantageously used is a mixture predominatingin, or containing a major proportion of, for instance about 65 to weightpercent, of one or more of the alumina trihydrates, bayerite,nordstandite or gibbsite, and about 5 to 35 weight percent of aluminamonohydrate (boehmite), amorphous hydrous alumina or their mixtures. Thealumina base can contain small amounts of other solid oxides such assilica, magnesia, natural or activated clays (such as kaolinite,montmorillonite, halloysite, etc.), Titania zirconia, etc., or theirmixtures.

The addition of the platinum group metal to the alumina or other solidrefractory type carrier can be accomplished employing, for example, theimpregnation methods described above in connection with the second stagehydroisomerization-hydrocracking catalyst. Also, as in the case of thecatalyst of the second stage, the platinum-group metal hydrogenationcatalysts used in the third stage of the process of the invention may beemployed in the form of macrosized particles generally having a diameterof about 1/32-inch to zfi-inch and a length of about l/l 6-inch to linchor more.

The process of the present invention is illustrated in detail by thefollowing example.

EXAMPLE A raw, waxy, mixed base lubricating oil distillate having an AP1gravity of 23.8; a flash point of5 10 F., a viscosity of 82.4 SUS at 210F., a pour point of F. and an aromatic carbon content of about 21percent, was contacted with hydrogen in the presence of a calcinednickel molybdate on alumina catalyst at a temperature of 700 F., apressure of 2,500 p.s.i.g., a weight'hourly space velocity of 0.25 and ahydrogen rate of 1,500 SCF/B of oil. The catalyst, which contained 2.3percent nickel and 15.6 percent molybdenum as the oxide, was pretreatedwith hydrogen sulfide at 350 F. for two hours using one SCF-H SIhrJ 100grams of catalyst. The hydrotreated product thus formed was flashed toremove light gaseous products and further treated in a second stage at atemperature of 750 F., a pressure of 2,500 p.s.i.g., a weight hourlyspace velocity of 0.35 and a hydrogen rate of 2,500 SCF/B of feed in thepresence of a calcined platinum-containing, silica-alumina-crystallinealuminosilicate extrudate catalyst. The catalyst contained about 0.5weight percent platinum, about 7 weight percent of about 90 percenthydrogen-exchanged crystalline aluminosilicate having a pore size ofabout 13 A. and a silica-to-alumina mole ratio of about 4 to 1, about82.5 weight percent silica-alumina xerogel containing about 13 weightpercent alumina, and about weight alumina added as a hydrogel.

The effluent product from the second stage was steam stripped to removehydrocracked components boiling below the lubricating oil range, andcontacted with hydrogen at a temperature of 550 F., a pressure of 2,500p.s.i.g., a weight hourly space velocity of 0.25 and a hydrogen rate of2,7500 SCF/B of feed in the presence of a platinum on alumina catalystcontaining 0.6 weight percent platinum. Technical grade white mineraloil was recovered in a yield of about 30 percent by weight.

it is claimed:

1. A process of producing a technical white mineral oil which comprisescontacting a raw, waxy mineral lubricating oil distillate having aviscosity of about 35 to 90 SUS at 210 F., an aromatic carbon content ofabout 15 to 30 percent, a pour point of at least about 70 F., andboiling primarily in the range of about 600 to 1,200 F., with hydrogenin the presence of a sulfur-resistant hydrogenation catalyst at atemperature of about 600 to 800 F. to provide a hydrorefined oil,contacting said hydrorefined oil with hydrogen in the presence of ahydroisomerization-hydrocracking catalyst comprising a major amount ofamorphous silica-alumina composite containing about 5 to 45 weightpercent alumina on a dry basis about 3 to 25 weight percent of an atleast about 50 percent hydrogen-exchanged crystalline aluminosilicatehaving a pore size of about 8 to 15 A., and a silica-to-alumina moleratio greater than 3:1. and about 0.1 to 5 weight percent of a platinumgroup metal at a temperature of about 600 to 950 F., removing componentsboiling below the lubricating oil range from the resulting product, andfurther contacting resulting hydroisomerized-hydrocracked productfraction of lubricating viscosity with hydrogen in the presence of ahydrogenation catalyst comprising a platinum group metal on a supporthaving no substantial cracking effect on saidhydroisomerization-hydrocracked product fraction, at a temperature ofabout 450 to 700 F. to saturate aromatics and produce technical whitemineral oil.

2. The process of claim 1 wherein the contact of said minerallubricating oil distillate with hydrogen and a sulfur-resistanthydrogenation catalyst is conducted at a pressure of about 500 to 3,000p.s.i.g., a weight hourly space velocity of about 0.2 to 2 and hydrogenfeed rate of about 1,000 to 5,000 SCF/B.

3. The process of claim 2 wherein the contact of saidhydroisomerized-hydrocracked product fraction with hydrogen is conductedat a pressure of about 500 to 3,000 p.s.i.g., a weight hourly spacevelocity of about 0.2 to 2 and a hydrogen feed rate of about 1,000 to5,000 SCF/B.

4. The process of claim 3 wherein the contract of said oil with hydrogenand the hydroisomerization-hydrocracking catalyst is conducted at apressure of about 500 to 3,000 p.s.i.g., a weight hourly space velocityof about 0.25 to 2 and a hydrogen feed rate of about 1,000 to 5,000SCF/B 5. The process of claim 1 wherein the platinum group metal of thehydroisomerization-hydrocracking catalyst and of the platinum groupmetal hydrogenation catalyst is platinum.

6. The process of claim 5 wherein the sulfur-resistant catalyst containsmolybdenum and an iron group metal supported on alumina.

7. The process of claim 6 wherein the iron group metal is nickel.

8. A process of producing a technical white mineral oil which comprisescontacting in a first stage a raw, waxy mineral lubricating oildistillate having a viscosity of about 35 to 90 SUS at 210 F., anaromatic carbon content of about 15 to 30 percent, and a pour point ofat least about F., and boiling primarily in the range of about 600 to1,200 F., with hydrogen in the presence of a catalytic amount of asulfided nickel molybdate supported on alumina catalyst at a temperatureof about 675 to 725 F., a pressure of about 2,000 to 3,000 p.s.i.g., aweight hourly space velocity of about 0.25 to 0.5 and a hydrogen feedrate of about 1,500 to 2,500 SCF/B to provide a hydrorefined oil,contacting said hydrorefined oil in a second stage with hydrogen at atemperature of about 650 to 800 F. in the presence of ahydroisomerizationhydrocracking catalyst which comprises a major amountof amorphous silica-alumina composite containing about 10 to 20 weightpercent alumina on a dry basis, about 5 to 10 weight percent of at leastabout percent hydrogen-exchanged crystalline aluminosilicate having apore size of 10 to 14 A., a crystal size of less than about 10 micronsand a silica-to-alumina mole ratio of about 4 to 6:1, and about 0.3 to 2weight percent of platinum, removing components boiling below thelubricating oil range from the resulting product, and further contactingthe fraction of the oil of lubricating viscosity from said second stagewith hydrogen in the presence of a platinumalumina catalyst containingabout 0.1 to 1 weight percent platinum at a temperature of about 550 to600 F., a pressure of about 2,000 to 3,000 p.s.i.g., a weight hourlyspace velocity of about 0.25 to 0.5 and a hydrogen to feed oil rate ofabout 2,000 to 3,000 SCF/B to saturate aromatics in said fraction, andrecovering resulting technical white mineral oil.

2. The process of claim 1 wherein the contact of said minerallubricating oil distillate with hydrogen and a sulfur-resistanthydrogenation catalyst is conducted at a pressure of about 500 to 3,000p.s.i.g., a weight hourly space velocity of about 0.2 to 2 and hydrogenfeed rate of about 1,000 to 5,000 SCF/B.
 3. The process of claim 2wherein the contact of said hydroisomerized-hydrocracked productfraction with hydrogen is conducted at a pressure of about 500 to 3,000p.s.i.g., a weight hourly space velocity of about 0.2 to 2 and ahydrogen feed rate of about 1,000 to 5,000 SCF/B.
 4. The process ofclaim 3 wherein the contract of said oil with hydrogen and thehydroisomerization-hydrocracking catalyst is conducted at a pressure ofabout 500 to 3,000 p.s.i.g., a weight hourly space velocity of about0.25 to 2 and a hydrogen feed rate of about 1,000 to 5,000 SCF/B
 5. Theprocess of claim 1 wherein the platinum group metal of thehydroisomerization-hydrocracking catalyst and of the platinum groupmetal hydrogeNation catalyst is platinum.
 6. The process of claim 5wherein the sulfur-resistant catalyst contains molybdenum and an irongroup metal supported on alumina.
 7. The process of claim 6 wherein theiron group metal is nickel.
 8. A process of producing a technical whitemineral oil which comprises contacting in a first stage a raw, waxymineral lubricating oil distillate having a viscosity of about 35 to 90SUS at 210* F., an aromatic carbon content of about 15 to 30 percent,and a pour point of at least about 70* F., and boiling primarily in therange of about 600* to 1,200* F., with hydrogen in the presence of acatalytic amount of a sulfided nickel molybdate supported on aluminacatalyst at a temperature of about 675* to 725* F., a pressure of about2,000 to 3,000 p.s.i.g., a weight hourly space velocity of about 0.25 to0.5 and a hydrogen feed rate of about 1,500 to 2,500 SCF/B to provide ahydrorefined oil, contacting said hydrorefined oil in a second stagewith hydrogen at a temperature of about 650* to 800* F. in the presenceof a hydroisomerization-hydrocracking catalyst which comprises a majoramount of amorphous silica-alumina composite containing about 10 to 20weight percent alumina on a dry basis, about 5 to 10 weight percent ofat least about 75 percent hydrogen-exchanged crystalline aluminosilicatehaving a pore size of 10 to 14 A., a crystal size of less than about 10microns and a silica-to-alumina mole ratio of about 4 to 6:1, and about0.3 to 2 weight percent of platinum, removing components boiling belowthe lubricating oil range from the resulting product, and furthercontacting the fraction of the oil of lubricating viscosity from saidsecond stage with hydrogen in the presence of a platinum-aluminacatalyst containing about 0.1 to 1 weight percent platinum at atemperature of about 550* to 600* F., a pressure of about 2,000 to 3,000p.s.i.g., a weight hourly space velocity of about 0.25 to 0.5 and ahydrogen to feed oil rate of about 2,000 to 3,000 SCF/B to saturatearomatics in said fraction, and recovering resulting technical whitemineral oil.